A motor vehicle of this type has become known as a “hybrid car” and is also called this in the text which follows. A hybrid car is equipped with two different motors, one internal combustion engine (Otto or diesel) and one electric motor. It is possible to switch from one motor to the other as desired using known technology. No exhaust gases are produced when the hybrid car is operated using the electric motor. This is particularly advantageous for city driving. The electric motor is fed with power from an energy source of appropriate size. The electric motor can also be operated such that it generates additional power when the internal combustion engine is also operating, so that both motors then act as a drive for the hybrid car. This option may be particularly advantageous when driving uphill but also during overtaking operations.
In the known technology, the electric motor is a three-phase AC motor which is operated by an inverter, which is likewise accommodated in the hybrid car, generating an AC current. The energy source is, for example, an energy store which comprises a large number of capacitors (ultracaps) and may be accommodated in the boot space of a hybrid car, for example. The capacitance of the capacitors is sufficient for brief operation of the electric motor. The said capacitors are recharged, for example during the braking mode, by the electric motor which then acts as a generator. In order to operate the electric motor, it is connected to the inverter by means of a three-core electrical cable, which inverter, for its part, is connected to the energy store via another electrical cable.
In the known cooling apparatus according to EP 1 538 885 A2 which was mentioned in the introduction, the energy source and the inverter and also a DC converter are positioned in a concentrated arrangement beneath a seat of the hybrid car. Just like the electrical cable which connects them, the energy source and the inverter are heat sources. They must be cooled in order to prevent undesired heating of the interior and excessive additional loading on any air-conditioning system which may be present. To this end, a fan is installed beneath the same seat as the abovementioned assemblies in the case of this known cooling apparatus. Cooled air is sucked in from outside the hybrid car by the fan via air-guide ducts, conducted past the abovementioned assemblies and expelled from the hybrid car in the form of heated air. This cooling apparatus is costly and often disturbingly loud on account of the fan.